Band making apparatus

ABSTRACT

Band making apparatus comprising a mandrel mounted for rotation about an axis, a source of wire, the wire having a pair of longitudinal channels arranged at the mandrel to open transverse to the axis, and a guide arranged to fit into one of the channels and biased toward the mandrel to hold the wire against it, the guide and the mandrel being arranged for a relative traverse motion along the axis while the mandrel is rotating, the rates of rotation and traverse being controlled in accordance with the dimensions of the wire to produce channel-to-channel interlock of successive turns of the wire of the mandrel.

United States Patent Zaltron July 8, 1975 I BAND MAKING APPARATUS Primary ExaminerC. W1 Lanham [75] Inventor. Mario Zaltron, Vicenza, ltaly Assismm Examinerakoben M. Rogers 173] Assignee: Evinger Corporation, Providence, An m Ag n or Firm-Edgar H. Kent 22 Filed: Jan. 28, 1974 ABSTRACT [2]] Appl. No.: 436,915 Band making apparatus comprising a mandrel mounted for rotation about an axis, a source of wire, the wire having a pair of longitudinal channels ar- [521 72/49; 72/139; 72/l44 ranged at the mandrel to open transverse to the axis, [5i] Int. Cl. 1321c 37/12 and a guide arranged to fit i one f the channels [58] Field of Search 72/49, 50, 144, I39 and biased toward the mandrel to hold the wire against it, the guide and the mandrel being arranged (56] References Cited for a relative traverse motion along the axis while the UNITED STATES PATENTS mandrel is rotating, the rates of rotation and traverse 915,673 3/1909 Heid 72/144 being controlled in accordance with the dimensions of 1,562,645 11/1925 Jones 72/144 the wire to produce channel-to-channel interlock of 1,617,583 2/1927 Fertress 72/49 successive turns of the wire of the mandrel. 2,314,510 3/1943 Odor 72/144 2,439,893 4/1948 [den 72/144 10 Clams, 9 Drawmg Flgures PATENTED 3 SHEET 2O 4? 00 FIG 4 BAND MAKING APPARATUS BACKGROUND OF THE INVENTION This invention relates to winding metal wire into bands, eg for use as watch bands.

Examples of bands of the general sort involved appear in U.S. Pat. Nos. 3,469,951 and 1,744,206, where wire having S-shaped cross-section is wound in a continuously self-interlocking fashion to product hollow bands.

SUMMARY OF THE INVENTION The invention provides machinery capable of automatically winding wire of the sort described, and interlocking successive turns to produce the desired band. The winding is even and neat, and can proceed continuously at high speed, producing any of a variety of desired band shapes (including, e.g., a reverse taper). The machinery is reliable, inexpensive, and easily operated.

In general the invention features band making apparatus comprising a mandrel mounted for rotation about an axis, a source of wire, the wire having a pair oflongitudinal channels arranged at the mandrel to open transverse to the axis, and a guide arranged to fit into one of the channels and biased toward the mandrel to hold the wire against it, the guide and the mandrel being arranged for a relative traverse motion along the axis while the mandrel is rotating, the rates of rotation and traverse being controlled in accordance with the dimensions of the wire to produce channel-to-channel interlock of successive turns of the wire on the mandrel. In preferred embodiments the traverse progresses alternately back and forth along the axis; the mandrel is tapered toward a free end to produce a continuous, reversely tapered band; the guide is a roller having a periphery sized to fit into the channel; a back-up member is biased against the mandrel opposite the guide, to balance forces on the mandrel; the guide and back-up member are freely rotatable rollers respectively mounted on arms pivoted in the apparatus and biased toward each other; the traverse motion is controlled by a rotatable cam having a heart-shaped cam surface, a follower arranged to follow the surface, and a linkage connected between the follower and the mandrel or the guide to produce the traverse motion in accordance with the rotation of the cam; and an element for applying tension to the wire presented to the mandrel is provided.

Other advantages and features of the invention will be apparent for the description and drawings herein of a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a band after being wound and cut off, but prior to final flattening;

FIG. 2 is a section view taken along 2-2 in FIG. 1',

FIG. 3 is a view similar to FIG. 1, after final flatten- FIG. 4 is a sectional view taken along 4-4 of FIG. 3 (omitting the surface design and the rolled edge);

FIG. 5 is a side view, partially sectioned, of part of the band making apparatus;

FIG. 6 is an enlarged end view, partially sectioned, of the apparatus;

FIG. 6a is an enlargement of a fragment of FIG. 6;

FIG. 7 is an overall, somewhat schematic view of the apparatus, showing the drive and control mechanism particularly; and

FIG. 8 is a plan view, partially sectioned, of the cutoff mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1-4, there is shown a band I0 (suitable, e,g., for use as one-half of a watch band) formed from generally helically wrapped metal wire 12. Wire 12 has a generally S-shaped cross-section, with generally planar segments 14, 16, 18, 20, and 22 (with curved transitions between adjacent segments) arranged somewhat in the form of a backwards Z. In particular, viewing segments I6 and 20 as being in horizontal planes, segments 14, 18, and 22 are parallel to each other and are tilted out of vertical planes by an acute angle (preferable l5", with a preferred range of 10-20) in the direction such that they make obtuse angles with the planes of segments 16 and 20. The wire material in the example shown is 0.0l0 inch thick (preferred range being 0.008-0.0l2 inch), and the spacing between adjacent segments 14, I8, and 22 is 0.05 inch. End segments 14 and 22 are somewhat shorter than middle segment 18. Segments 20 and 16 ultimately form the outside and hidden internal surfaces 17 and 19 of the band, respectively. Segment 18 connects the two surface forming segments, and, with the end segments, defines oppositely opening channels 21 and 23.

As described in more detail in connection with the apparatus of FIGS. 5-8, the wire is wrapped with segment 14 of each, turn interlocked in channel 23 between segments 18 and 22 of the previous turn, and with segment 22 similarly interlocked in channel 2I. Since the channels are only slightly wider than the metal thickness, segments 14 and 22 will each contact, at least at the band edges, both opposing side walls of the respective channels in which they are interlocked, bringing successive turns of segments 16 adjacent each other and into a common, fairly smooth surface. After winding, the resulting band-like tube 24 (FIG. I is flattened between die plates at extremely high pressure to bring the opposing portions of internal surface 19 of the tube into contact, increasing the angle between segments 14, 18, and 22 and the vertical (the increase in the example shown being to 30). The initial tilt of segments l4, l8, and 22 from the vertical ensures that during the flatteningprocess all of those segments will bend in the same direction, so that the resulting outer surface of the band will be smooth. If desired, the flattening dies may bear a design to be impressed upon the band, as shown in FIG. 3. The general smoothness of the band surface, with relatively short gaps between adjacent segments 20, makes possible excellent definition of such a design. The fact that segments 16 and 20 are initially planar minimizes the amount of metal deformation required furing the flattening process to achieve the desired band surface, especially when a design is to be impressed, and makes possible the use of relatively heavy gauge wire to produce a band having substantial weight, feel, and appearance. The fact that segments 14, 18, and 22 are planar and (at least initially) parallel to each other enhances the positive, tight interlock of successive wire turns, further contributing to a smooth band surface. Rolled edges 26 and 28 may also be impressed upon the band by the dies, helping to lock adjacent turns of the wire against-relative lateral shifting in the event cutouts (e.g., holes for a buckle tongue) are included in the final design of the band.

Referring now to FIGS. 5-8, wire 12 is supplied to the wrapping apparatus from tapered spool 40 (FIG. 7) freely rotatable on pedestal 42. The wire passes through tension device 44 (FIG. 5) having nylon blocks 46 and 48, shaped to fit into the channels of the wire, and adjustable thumb screw 50 hearing against block 46 to control the tension on the wire. The wire then passes freely between pivoted arms 52 and 54, through guide 56 having a cutout in the shape of the wire, past outboard side guide 58, to tapered, blade-shaped winding mandrel 60 (see especially FIG. 6). In the example shown the blade is 0.050 inch thick and ranges in width from 3/16 inchat its tip to 9/16 inch at its base.

Guide roller 70 is freely rotatable on shaft72 journaled in adjustable universal head 74 on arm 54 just below blade'60. Roller 70 has a peripheral flange 76 sized (0.013 inch thick) to fit snugly into the downwardly opening channel 21 of wire 12 as the wire passes beneath blade .60. Head 74 is adjustable to allow roller 70 to be tilted slightly (preferably about 1 /2") toward wire segment 18. Such. tilt of the roller has been found to improve control over the wire during the winding process. Flange 76 has its peripheral surface 77 ground at a slight angleto bring that surface as closely as possible into area contact with the inner surface of wire segment 16. The relatively large area of effective contact betweenplanar segment 16 and blade 60 further enhances control over the wire, and makes possible very high speed winding. Balance wheel 80 is freely rotat able on shaft 82 journaled at the end of arm 52 just above blade 60, and is offset slightly inboard of roller 70. Spring 84 extends between brackets 86 and 88 respectively attached to arms 52 and 54 to bias the arms toward each other (with some to 18 pounds of force), thereby holding roller 70 in the channel of the wire being wound on blade 60, and holding roller 80 against the top of the blade to balance the forces thereupon and prevent whipping of the blade.

Blade 60 is mounted at the end of shaft 90 for rotation about horizontal axis 92, and passes (with a sliding fit) through slot 94 of guide block 96. Guide 96 is mounted forl rotation about axis 92 in roller bearing 98 in support 100. Support 100, guide 56, tension device 44, and arms 52 and 54 are mounted on carriage 102 which is in turn mounted to slide (FIGS. 5, 7) on rods 104 and 106 for traverse parallel to axis 92. For moving the carriage along rods 104 and 106 rod 108 is rigidly attached to the carriage and slides at its free end in block 110. Bracket 112 is attached to rod 108 and carries a member 114 which receives with a sliding fit stub shaft 116 extending from link 118. Link 118 is pivoted on pin 122 in slot 120 and carries a cam follower 124 which follows heart-shaped track 126 in cam 128. Pin 122 is mounted on link 130 which in turn can be adjusted in slot 132 of the machine frame by loosening bolt 134. Cam 128 is mounted on shaft 136 for rotation therewith. and controls the traverse of carriage 102 as described in more detail below. A second track 126' in cam 128 is provided for a shorter traverse cycle, used in making shorter bands.

Shaft 90 is supported in frame-mounted roller bearings 138 and 140. Hand wheel 142 allows manual rotation of shaft 90 during start-up of the machine. Drive chain 144 extends between sprocket wheel 146 on shaft and sprocket wheel 148 on the drive shaft of variable speed motor 150, for rotating shaft 90 at a precisely controlled rate, with no slippage in the drive train. Motive power from motor 150 is used to drive cam shaft 126 through variable speed reducer 152, and reductor 154, connected by belt 156 and chain 158; sprockets 160 and 162 mounted on shaft 164, connected to reductor 154 by chain 166; and sprocket 168 mounted on shaft 136 and connected by chain 170 to sprocket 162. Idler sprockets 172 and 174 provide tension in chains 166 and 170, respectively. The gear ratio of reducer 152 can be adjusted to control the ratio of rotation rates of shaft 90 and shaft 136, in turn controlling the ratio of the traverse rate of carriage 102 to the rotation rate of blade 60, so that the pitch of the flattened helix wound on the blade is coordinated with the dimensions of the wire to produce the desired interlock of successive wire turns.

Block (FIG. 5) of rectangular cross-section is pivotally supported between arms 52 and 54 near their pivoted ends. Lever 182 is connected to block 180 for turning the block between a horizontal position (dashed lines, FIG. 5) out of contact with the arms, and a more nearly vertical position (solid lines, FIG. 5) in which the block forces the arms apart to allow threading of wire 12 into the machine for start-up. Safety latch 184 is provided to lock lever 182 in the open arm position.

In operation of the apparatus thus far described, with arms 52 and 54 held apart by block 180, wire 12 is threaded through tension device 44 and guide 56 and is wrapped by hand one turn around blade 60, interlocking segment 14 near the free end of the wire in the adjacent channel of the first wire turn. Hand wheel 142 is used to aid this initial wrapping. Lever 182 is moved to close the arms, bringing flange 76 of roller 70 into the downwardly opening wire channel, and bringing roller 80 into contact with blade 60 from above. Hand wheel 142 is rotated to wind a few turns of wire on blade 60 by hand, checking to see the successive turns properly interlock.

Motor 150 is then turned on to run continuously. As cam 128 rotates carriage 102 is traversed back and forth parallel to axis 92, reversing direction upon each 180 of cam rotation. Considering the traverse from left to right, the turns of wire will begin near the blade tip and progress along blade 60, successive turns being of increasing diameter in accordance with the taper of the blade. Arms 52 and 54 will open and close upon each revolution of the blade, with spring 84 always holding roller 70 against the wire and roller 80 against the blade. When the carriage reverses direction successive wire turns will progress from right to left on the blade, will have decreasing diameter, and will force the earlier wound turns to slide off the free end of the blade. Upon completion of the right to left traverse only a few turns will be left on the blade, and carriage 102 will again reverse direction, repeating the cycle just described, and so on. There is thus produced a continuous, reversely tapered band. The shape of the band may be varied by changing the shape of the blade, with the repetition length of that shape being determined by the diameter of the cam track 126, 126'. The uniform thickness of the planar segments of the wire facilitates high speed winding without kinking.

As the wound band 200 (FIGS. 6-8) slides off blade 60 it enters receiving tube 202 of automatic cut-off unit 204. Within unit 204 knives 206 (FIG. 8) are mounted to reciprocate along axis 208 at 90 to axis 92. Knife return springs 210 bias the knives out of engagement with each other, and rocker arms 212, pivoted at 214, act against the outside ends 216 of the knives for forcing them against springs 210 during the cutting stroke. Cutoff cam 2l8, driven by motor 220 through electric clutch-brake 222, is mounted between cam following rollers 224 at ends 226 of arms 212. When cam 218 has its short axis extending between rollers 224 springs 210 hold the knives out of engagement. When the cam rotates 90 so that its long axis extends between the rollers, the knives are forced together to cause blade portions 230 to cut band 200 passing therebetween. To produce a rapid cut, capable of being accurately timed, cam MS has relatively sharp transition portions 232, and extended dwell portions 234. It is important that the cuts be accurately timed, not only to produce band segments of the desired length, but to avoid cuts when the band (which is continuously rotating with blade 60) has its edges presented to the knives. The timing system is as follows.

Timing cam 250 (FIG. 7) on shaft 164 has fingers 252 spaced 180 apart and arranged to trip limit switch 254 upon each half revolution of cam 128. The fingers are arranged so that one cut occurs half way through the right to left traverse, and the other cut occurs during the left to right traverse; the latter cut could take place any time during the left to right traverse, since the band does not feed off blade 60 during that traverse. Switch 254 triggers level amplifier 256 in electronic control unit 258 (a conventional unit available from Warner Electric Brake and Clutch Co., Beloit Wisconsin), which produces a sharp pulse to engage the clutch in unit 222, transmitting power from continuously running motor 220 to cam 218. Cam 218 has two reflective tape targets 260 slightly offset angularly (clockwise) from opposite ends of the long cam axis. As the cam rotates clockwise, forcing rollers 224 apart to cut the band, then allowing the blades to disengage as rollers 224 reach dwell portions 234, photoelectric scanner 262 will signal when a target 260 crosses plane 264 (FIG. 8) lying between arms 212 and perpendicular to axis 208. Scanner 262 signals impulse amplifier 266 which in turn disengages the clutch and applies the brake in unit 222, stopping cam 218 (which overtravels the stop signal slightly due to inertia) within a very short period (in the embodiment described, about 3 micro-seconds) after the sensing of target 260. Thus, in effect, the cam stopping procedure is initiated at precisely the same point in each cutting cycle, even though the actual point in the cycle at which the cam is brought to rest may vary slightly from cycle to cycle. As a result, inertia produced variations in the stopping point do not accumulate from cycle to cycle, and the cutting moment can be accurately timed. The position of cam 250 on shaft 164 should be such that the cut occurs when the flat surface of band 200 is within 30 of being perpendicular to knife axis 208.

The automatic cut-off unit is important to continuous operation of the winder in that it limits the length, and hence the whipping action which would otherwise build up, of the rotating band extending from blade 60.

Each band segment cut off is ejected from the cut-off unit by air from tubes 270, 272 (FIG. 7), controlled by timing cam 274 on shaft 164, which operates limit switch 276, and is then stamped as desired in die unit 280. The flattening of the band, bringing the opposing interior surface portions into contact, serves in addition to make the band more flexible (i.e., bendable), since the length of the wire portions extending transverse to the main band surfaces, along the band edges, is reduced.

Unit 280 is, in the example shown, a hydraulic press separate from the rest of the apparatus, and employs a spring padded die in a cavity sized to receive the band segment.

I claim:

1. Band making apparatus, comprising a mandrel having an axis,

a source of wire, said wire having a pair of oppositely opening longitudinal channels, said source including means for presenting said wire to said mandrel with said channels opening in opposite directions transverse to said axis,

a guide arranged to fit into one of said channels,

means for relatively rotating said mandrel and said guide about said axis of said mandrel to wind said wire about said mandrel,

means for biasing said guide toward said mandrel to hold said wire against said mandrel,

means for providing a relative traverse motion between said guide and said mandrel during the relative rotation thereof, and

means for controlling the rates of said relative rotation and said traverse motion in accordance with the dimensions of said wire to produce channel-tochannel interlock of successive turns of said wire on said mandrel.

2. The apparatus of claim 1 wherein said means for providing said traverse motion includes means for causing said traverse to progress alternately back and forth along said axis.

3. The apparatus of claim 2 wherein said mandrel is tapered toward a free end, whereby said back and forth traverse causes a continuous, reversely tapered band to be fed from said free mandrel end.

4. The apparatus of claim 1 wherein said guide is a roller having a periphery sized to fit into said channel.

5. The apparatus of claim I further comprising a back-up member biased against said mandrel opposite said guide, to balance forces on said mandrel.

6. The apparatus of claim 5 further comprising a pair of arms pivoted in said apparatus and biased toward each other, said arms respectively carrying said guide and said back-up member.

7. The apparatus of claim 6 wherein said guide and back-up member are freely rotatable rollers.

8. The apparatus of claim 2 wherein said means for providing said traverse motion comprises a rotatable cam having a heart-shaped cam surface, a follower arranged to follow said surface, and a linkage connected between said follower and said mandrel or said guide to produce said traverse motion in accordance with the rotation of said cam.

9. The apparatus of claim 1 further comprising means upstream of said mandrel for applying tension to said wire presented to said mandrel.

10. The apparatus of claim I wherein said mandrel is mounted for rotation about said axis. 

1. Band making apparatus, comprising a mandrel having an axis, a source of wire, said wire having a pair of oppositely opening longitudinal channels, said source including means for presenting said wire to said mandrel with said channels opening in opposite directions transverse to said axis, a guide arranged to fit into one of said channels, means for relatively rotating said mandrel and said guide about said axis of said mandrel to wind said wire about said mandrel, means for biasing said guide toward said mandrel to hold said wire against said mandrel, means for providing a relative traverse motion between said guide and said mandrel during the relative rotation thereof, and means for controlling the rates of said relative rotation and said traverse motion in accordance with the dimensions of said wire to produce channel-to-channel interlock of successive turns of said wire on said mandrel.
 2. The apparatus of claim 1 wherein said means for providing said traverse motion includes means for causing said traverse to progress alternately baCk and forth along said axis.
 3. The apparatus of claim 2 wherein said mandrel is tapered toward a free end, whereby said back and forth traverse causes a continuous, reversely tapered band to be fed from said free mandrel end.
 4. The apparatus of claim 1 wherein said guide is a roller having a periphery sized to fit into said channel.
 5. The apparatus of claim 1 further comprising a back-up member biased against said mandrel opposite said guide, to balance forces on said mandrel.
 6. The apparatus of claim 5 further comprising a pair of arms pivoted in said apparatus and biased toward each other, said arms respectively carrying said guide and said back-up member.
 7. The apparatus of claim 6 wherein said guide and back-up member are freely rotatable rollers.
 8. The apparatus of claim 2 wherein said means for providing said traverse motion comprises a rotatable cam having a heart-shaped cam surface, a follower arranged to follow said surface, and a linkage connected between said follower and said mandrel or said guide to produce said traverse motion in accordance with the rotation of said cam.
 9. The apparatus of claim 1 further comprising means upstream of said mandrel for applying tension to said wire presented to said mandrel.
 10. The apparatus of claim 1 wherein said mandrel is mounted for rotation about said axis. 